(kād'mē-əm) Symbol CdA rare, soft, bluish-white metallic element that occurs mainly in zinc, copper, and lead ores. Cadmium is plated onto other metals and alloys to prevent corrosion, and it is used in rechargeable batteries and in nuclear control rods as a neutron absorber. Atomic number 48; atomic weight 112.41; melting point 320.9°C; boiling point 765°C; specific gravity 8.65; valence 2. See Periodic Table.